Just asking, why are you selling your PS4? There's been a few decent exclusives on the PS4 in the last few months like Yakuza, Nier, Nioh, Horizon and Persona 5.
I would never sell a Xbox or PS4 to buy a switch unless you got a good gaming PC. As I don't think third party publishers will treat it seriously.
Yeah, it'd be pretty daft to sell a PS4 and buy a Switch as your only console.